Diamond lap



April 19 1927. 1,625,463

E. GAUTI -IIER DIAMOND LAP Filed Dec. 29. 1922 liwerzifir ErnesT Gazflhier showing Patented Apr. 19, UNITED [STATES PATENT OFFICE;

ERNEST GAUTHIEB, OF CHICAGO, ILLINOIS, ASSIGNOR TOWEBTEBN ELECTRIC COM- PANY, INCORPORATED, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK DIAMOND LAP.

Application filed December 29, 1922. Serial No. 809,645.

eriphery of a metallic arbor, the project-.

ing points of the particles serving as cutters. Laps made in this way are open to the serious objection that the particles become dlS- lodged from their seats in the arbor within a short time and before they have outworn their usefulness. As a result the eflicient working life of the la is-of short duration:

In accordance with t e present invention a grinding implement is produced comprising a suitable arbor and a grinding element composed of abrasive material and a suitable binder moldedunder pressure to constitute a unitary structure and suitably attached to the arbor. In its preferred form the invention'comprises a lap consisting of an arbor and a grinding element'- composed ofjdiamond splints or particles, and a metallic binder, in powdered form, molded under pressure into a-unitar structure, the grinding element thus pro uced being simultane ously molded onto the arbor.

The accompanyingdrawing illustrates a lap made in accordance with the invention and a method by which the same may be produced, and in which,

Fig. 1 is a vertical sectional view, parts shown in the elevation, illustrating an apparatus by which the grinding element may be made'and attached to the arbor, and a lap in theprocess of made thereby; u I "r' -Fig. 2 is a fragmentary top plan view thereof, and,

Fig. 3 is 'a of a completed lap.

In making a lap in accordance with the present invention an arbor 10 isset in an upright osition' within an openin made in a suita le base block 11 to receive it. The arbor 10 maybe of any suitable construction, but preferably made of steeland hav ing a portion of its periphery corrugated or fluted in the manner indicated at 12, the purpose of .which will be hereinafter delongitudinal sectional view duces a scribed. After the arbor has been mounted in position, a mold 13 is fitted within a-cupshaped opening 14'of a size and shape to receiveit, made in the base block 11. The mold is provided with a cylindrical opening 15 to receive the material to be molded, this opening communicating with a central orifice through which theifiuted end 12 of the arbor 10 Fig. 1. mixture composed of articles of abrasive material and particles 0 a suitable binder is then deposlted'in'the' opening 15 in the mold. The volume of the mixture placed in the mold may vary in amounts partially or completely filling theopening, according to the size of the grinding element desired. Any'suitable abrasive and binding ingredients may be used to constitute the mixture, but in making diamond laps, preferably diamond splints and a binding material consisting of powdered metal is utilized. It will be found that a more uniformly molded grinding element will be produced if ametallic binder is utilized'free from impurities, and for this reason preferably electrolytic metal should be used as thebinder. I have experienced very satisfactory results using electrolytic iron in a mixture of 66%- electrolytic iron and 34% diamond particles. After the abrasive mixture has been placed in the mold, a'plunger or ram '16 is caused to descend, the ram being of a size to en-' ter' the opening in the mold and having a central opening 17 to receive the projecting end of. the arbor 10. The ra ii I operated by hydraulic pressure or other suit- Lprojects in' the manner shown in 16 may be able ineansv to exert suitable pressure upon I the abrasive mixture within. the mold.

The mixture within the .mold' is subjected to sufiicient pressure by the ram 16 to mold diamonds and binder, together with the,

amount,- of pressure to be exerted by the ram 16, should vary according to the hardness which it is desired that the molded grinding element should have. I have found that'a mixture of 66% ;lectr0lytic, iron particles and 34% diamond particles molded nude! pressure of tons per square inch pro- 'inding element capable of holding the diamond particles firmly enough for .it into ahomogeneohs aggregate which is interlocked, with the ridges and depressions:

ractical dang urpolses, and-isuiot ilard hut ill: it will wear down asthe diamond particles become dulled so that they; may be wrenched out of their position to expose new diamond particles to the grindin face.

he great efliciency of. a lap gnadein ac! cordance with the present invention as compared with aiap made by forcing diamond splints into-:1. metallic arbor may be made clear by 'aacomparativetest of the two laps. Usin the old type oflap tolap out a hole "ina ardened steel piece," I found that in an hours time the lap had enlarged the hole by .015. 'In la'lpping' a similar hole" in the a ap same stockwit made inaccordance with the resent invention, '1 found that in- 5 .an hour t e hole had been. enlarged by .049, .In other words,,1 find that when the two lapsare used under the same conditions, the

lap of-the present invention will cut approximately three times asmuch metal in a givenverted. By tapping the end of the. arbor lowith a punch or other suitable device,

the completed laptoget-her with the mold 13-.

.will drop out of the base block. The mold 13 is made in three segments and isreadil removed by striking it against thebase bloc 'or iving it a blow' with a hammer, which gmentsoto fall away from inding element.

wilicause ,the' se the molded -Whet is c aimed 1s: 1. A. newarticle of manufacture-comprising/ diamond= articles and finely divided.

metallic partic es molded into ahomogeneou 'g '-2.- A new article of manufacture comprising diamond articles and electrolytic metal garticles-mol ed under pressure to form a" omogeneous aggregate. Y

'3. A new article of manufacture compriamg diamond particles and electrolytic iron particles in a finel divided form molded under pressure to mm a homogeneous aggregate. v p 4. A new article of manufacture comprising diamond particles about 66% and electrolytic iron particles about 34 .percent molded under pressure to form a homogene ous aggregate. a

In witness whereof, I hereunto subscribe my name this 20th day offDe'cember,A-. 1).,

ERNEST GAUTHIER. 

